In general, a rear wiper sometimes needs to be installed on a rear glass of a vehicle according to an inclined angle of the rear glass. A rear wiper is not generally provided on a rear glass of a vehicle of a notch-back style that is called a sedan, but on a hatch-back style vehicle such as a sports utility vehicle (SUV) that essentially has a rear wiper on a rear glass thereof, because that dust is likely to get stuck on the rear glass due to low pressure on the rear glass during driving.
An example of a vehicle having a conventional rear wiper 1 on a rear glass thereof is shown in FIG. 1. In general, a rear wiper consists of a plurality of components. Such a wiper device is disclosed in Korean Patent Publication No. 0500581.
A conventional wiper device 1 includes an arm head 2 driven by a wiper motor (not shown), a retainer 3 coupled to the arm head 2, and a wiper blade 4 detachably assembled on the retainer 3. The wiper blade 4 is generally an expendable component that is worn by glass, and thus, is frequently replaced with a new one.
Therefore, the wiper blade 4 is assembled so as to be detached at a position rotated at a predetermined angle with respect to the retainer 3 as shown in FIG. 2. That is, as shown in FIG. 2, the wiper blade 4 includes a rotary shaft 5 having a non-circular cross section, and the retainer 3 includes a circular recess 6 having an opened side to receive the rotary shaft 5. The circular recess 6 may be coupled to the rotary shaft 5 at only a predetermined angle. That is, the non-circular cross section of the rotary shaft 5 passes through the opened side of the circular recess so that the wiper blade 4 and the retainer 3 are coupled to or separated from each other. However, the non-circular cross section of the rotary shaft 5 is invisible from outside in a state where the wiper device 1 is installed on a vehicle. Therefore, when a user wants to replace the wiper blade 4 with a new one, the user has to find the non-circular cross section of the rotary shaft 5 instinctively while rotating the wiper blade 4 relative to the retainer 3, and thus, the user may be inconvenienced. Also, since the user may not know the separating position of the wiper blade 4 exactly, the wiper blade 4 or the retainer 3 is likely to be damaged if the user forcedly separates the wiper blade 4 from the retainer 3.